1. Field of the Invention
The present invention relates to a coordinate measuring machine.
2. Description of Related Art
A typically known coordinate measuring machine includes: a probe having a measurement piece that moves within a predetermined range while being in contact with an object to be measured: and a drive mechanism that supports and drives the probe, where the object is measured based on the displacements of the measurement piece and the probe (see, for instance, Literature 1: JP-A-2008-89578).
A surface-profile measuring instrument (coordinate measuring machine) disclosed in Literature 1 includes: a scanning probe having a measurement piece; and a drive mechanism. The surface-profile measuring instrument acquires the displacements of the measurement piece and the probe while the measurement piece is pushed against an object, the acquired displacements being combined to measure the object.
Since such a coordinate measuring machine employs a drive mechanism for moving the measurement piece to measure an object, it is required that the coordinate measuring machine has a measurement space of a volume larger than the object in order to measure the object. Accordingly, when a large-size object such as a vehicle component is to be measured, a large-size coordinate measuring machine has to be used.
When a large object on which a plurality of small holes are consecutively formed at predetermined intervals is measured by a coordinate measuring machine, it sometimes occurs that the diameter of each of the holes has to be precisely measured but the pitches between the holes do not have to be measured with a high accuracy. In other words, there sometimes is a mixture of a small area and a large area on an object, the small area requiring highly accurate measurement, the large area requiring not so much accurate measurement.
However, according to the coordinate measuring machine disclosed in Literature 1, the large area has to be measured with an expensive coordinate measuring machine having a measurement accuracy corresponding to the small area that has to be highly accurately measured.
Further, since a large-size coordinate measuring machine requires a large drive mechanism, it is difficult to measure the small area at a high speed.